1. Field of the Invention
The present invention relates to a two-shaft extruder comprising a pair of rotor shafts rotatably disposed with a distance therebetween diminishing toward the leading ends thereof, a screw blade mounted to the leading end of each one of the pair of rotor shafts, one screw blade intruding into the pitch of the other screw blade; and a drive unit mounted the base end of each one of the pair of rotor shafts for rotatably driving the rotor shaft associated therewith.
2. Description of the Related Art
Such two-shaft extruder is configured to be capable of extruding an amount of high-viscosity substance such a un-formed rubber material, plastic material charged therein while kneading the substance with the screw blades.
Conventionally, with a two-shaft extruder, in general, as shown in FIG. 9, a motor M with a reduction mechanism is mounted as a drive unit to the base end of one rotor shaft 1a alone. Whereas, a conical gear 15 is attached to each one of the pair of rotor shafts 1. In operation, as the motor M rotatably drives the one rotor shaft 1a, the other rotor shaft 1b is rotated in association therewith through the meshing engagement between the pair of conical gears 15. In contrast, there has been proposed a different type designed to allow use of more inexpensive conical gears through reduction of the load applied to the pair of conical gears 15 for transmitting the rotational drive force, in which a drive unit for rotatably driving a rotor shaft is mounted to the base end of each one of the pair of rotor shafts and a pair of conical gears are provided to the pair of rotor shafts respectively, such that the pair of drive units drive the pair of rotor shafts respectively in synchronism with each other through meshing engagement between the conical gears while avoiding contact between the screw blades of the rotor shafts (see e.g. Patent Document 1).    Patent Document 1; Japanese Patent Application “Kokai” No. Hei. 9-164578.